SpaCBA ‐ OVA Liposome Reprograms Immune Tolerance to Ameliorate Allergic Rhinitis via DC ‐T Cell Crosstalk

ABSTRACT Allergic rhinitis (AR) is a prevalent immune disorder driven by Th2‐polarised inflammation, with current therapies primarily providing symptomatic relief rather than addressing the underlying immune dysfunction. Allergen‐specific immunotherapy (AIT) holds promise for inducing long‐term tolerance but is limited by poor mucosal delivery, enzymatic degradation of antigens, and inconsistent efficacy. A liposomal formulation co‐encapsulating SpaCBA (probiotic protein) and ovalbumin (OVA) was engineered. Characterisation included in vitro/in vivo evaluations of immune modulation and therapeutic efficacy in a murine AR model. The SpaCBA‐OVA liposome exhibited stable characteristics (size: 100 ± 25 nm; zeta potential: −22 ± 3 mV; 85% entrapment efficiency) and enhanced proteolytic resistance (> 70% protein integrity after 48‐h trypsin exposure vs. > 90% degradation of free proteins). Bone marrow‐derived DCs (BMDCs) internalised the liposome 3–3.5× more efficiently via CD206/TLR2, adopting a semi‐mature (CD86low/MHC‐II high ) phenotype and secreting IL‐10 (320 ± 30 pg/mL) and TGF‐β (280 ± 25 pg/mL). RNA‐seq identified 980 differentially expressed genes in T cells, with upregulation of Treg markers (FOXP3, IL‐10) and downregulation of Th2 factors (GATA3, IL4). Epigenetic analysis confirmed 55% demethylation of the FOXP3 promoter. In AR mice, the liposome reduced sneezing and nasal rubbing by 60%–65% ( p < 0.001), decreased nasal eosinophils by 55%, normalised ZO‐1/occludin expression (90% of controls), and reduced epithelial permeability (FITC‐dextran flux). The SpaCBA‐OVA liposome enhances mucosal delivery and stability of antigens, reprograms DCs to induce Treg‐mediated tolerance via metabolic and epigenetic mechanisms, and effectively ameliorates AR pathology in mice. This formulation represents a promising targeted therapy for AR, addressing key limitations of current AIT.